The aerodynamic effect of aerodynamically active aircraft components, such as wings, vertical and horizontal tail planes, rudders, control flaps, slats and high lift devices is based to a large degree on the profile or characteristics of the flow established in flight above the surface of the respective aircraft component. When it is desired to be able to selectively influence the flow so-called vortex generators may be provided. Vortex generators are projections arranged on flow surfaces of aircraft components and adapted or configured to selectively generate vortices or turbulence in the region of the boundary layer between the flow over the flow surface and the flow surface and to thereby supply energy to the flow. This may be advantageous, e.g., when it is desired to achieve a maximum possible aerodynamic effect of an aerodynamically active aircraft component.
The effect of vortex generators is advantageous predominantly in particular flight or operating conditions or situations. However, vortex generators also tend to increase drag. For this reason, selectively extendable and retractable vortex generators are known, which are, if possible, only extended in selected situations and maintained in the retracted condition otherwise in order not to increase drag.